After reading the "Where Do you design at ?" thread. I decided to post a pack of my creation I have been using for a while it called the FTZP day pack or Flip Top Zip Top day pack. I used my bendable ruler to design it.

So here it it is the FTZP day pack it about 15 liters what nice about it has waterproof zipper top closer that can be flipped over for smaller loads and left extended for a larger load. It has silver Xpac back and bottom,Thru hiker grid X dyeemna for the rest of the pack fabric.I used 5/8 inch webbing for the straps and compression straps,It has no waist belt and all ITW Nexus hardwear: Jet ladder lock buckles,Sternum strap hardware,Pack cord management hooks.
I decided to do a experiment with a fully breathable shoulder straps using only 3D foam mesh back to back. Instead of of using Cross grain ribbon I used 1 inch flat webbing folded over on the edges of shoulder straps
I have found it is a very strong shoulder strap construction method but it not a soft pliable edge as cross grain ribbon. I also used stretchable mesh pockets with elastic webbing edging.

The pack cord management hooks are sewed to Hypalon patches use a loop of elastic cord to connect the to hooks when lid is flipped down.Compressed 1/4 inch foam back pad insert for the back.

FTZP photos:

I have been getting older I really need a internal frame pack in larger packs for myself for hauling heavier loads. I really like the Mystery ranch packs futura frame system. I do not have the money or proper equipment to make larger packs of my dreams. So I am going to stick to small day packs with my home machine.
I think the FTZP Pack Design at about 25 liters would make a great over night SUL weight summer pack for the SUL crowd.
Terry

Chase,
Thank you for the kind comments on my pack design.
I use to own a electronic postal scale when I was flying RC hand launch gliders because you really had to shave grams to make a glider with a lower weight wing loading. Then the scale fell off my work bench and broke.

With backpacking I usually just pack it with my gear and weigh myself with out the pack on and then the pack on. Do the math to find out heavy my backpack load will be on trip. Plus I am more concerned with the total overall weight of what will be on my back for that trip.

I also have better things to spend my money on than postal scale right now in my life. When I do want to weigh individual equipment I made. I go to the post office and use their scales because their very accurate because the post office has them calibrated every few months .

When I do guesstimating I have canned foods in varying weight.I hold the can in one hand and the pack in the other to get a feel for the weight. Then I switch can and pack to other hand if it feels lighter than the can.I know it lighter than measured can food weight.
Terry